The tissue core will process human articular cartilage and isolate chondrocytes. Cells will be stimulated in high density primary culture or in alginate beads and provided to the projects for experiments. Protein and mRNA extracts will be prepared from these specimens. The studies proposed in all research components depend on these samples and this core is thus essential to the success of the program. The specific functions of the core are: 1) Isolation of chondrocytes and meniscus cells. 2) Isolation of RNA from each donor knee. 3) Maintenance of a cell bank with chondrocytes from different age groups. 4) Chondrocyte cultures in monolayer and alginate. 5) Preparation of cells, conditioned media, protein and nucleic acid extracts from different culture systems and stimulation conditions. 6) Biomechanical stimulation of tissue explants.